According to the study, the number of deaths resulting from motorcycle accidents has risen in 14 out of the last 15 years. From 2011 to 2012 alone, motorcycle-crash related deaths have risen nine percent to approximately 5,000 lives lost.

One of the main safety measures emphasized in the GHSA study is the use of motorcycle helmets, which is in decline.

And on Thursday, another study was released, further emphasizing the use of helmets – the Highway Loss Data Institute’s (HLDI) “Michigan’s weakened helmet use law leads to costlier injury claims.”

The study shows that since Michigan repealed its universal helmet law in 2012 (one of six states to do so), the medical costs of injured motorcyclists increased substantially, while motorcycle injury crashes also increased.

The GHSA reports that “this is consistent with many previous studies showing that repealing a law requiring all riders to wear helmets inevitably and quickly increases motorcyclist fatalities.”

To date, only 19 states (plus the District of Columbia, Northern Mariana Islands, Puerto Rico, U.S. Virgin Islands) currently have universal helmet laws that requires helmets for all riders, and the last one to reenact the universal helmet law was Louisiana in 2004.

All together 47 states have helmet laws, but the remaining 28 (not included 19 listed above) have laws for specific riders (usually 18- or 20-years old or younger).

The GHSA looks down on only 19 states having mandatory helmet use, considering “helmet use has been cited by researchers as the single most effective countermeasure in reducing motorcyclist injuries and deaths.”

The GHSA says: “The new data from HLDI adds to the evidence that motorcycle safety is going in the wrong direction. Earlier this month, the National Highway Traffic Safety Administration (NHTSA), reported that helmet use declined six percentage points in 2012, to 60 percent.

“While the news about motorcyclist safety continues to be disheartening, there is no mystery about what should be done to keep riders safe.”

The GHSA urges states to address six main motorcycle-safety issues:

Increase helmet use

Work to reduce alcohol impairment among motorcyclists

Work to address speeding among motorcyclists

Increase operator training opportunities

Ensure operators are properly licensed

Encourage all drivers to share the road with motorcyclists

For additional information on motorcycle-helmet laws, including a chart of all states that have helmet laws, click here.